DETROIT – Johnny Manziel was all smiles when Kyle Shanahan stopped by his stall in the visitor's locker room at Ford Field on Saturday night for a quick chat.

That Manziel still had a bounce in his step as he headed to the buses was a good sign, too.

Manziel made his NFL preseason debut against a cast composed primarily of Detroit Lions backups, and he survived. During a quarter-and-a-half of work after relieving Brian Hoyer, he looked like he belonged on an NFL stage. Even added a spark.

Yet the same element of Johnny Football that undoubtedly excites the long-suffering Cleveland Browns fans is the same element that will make them worry.

Johnny Football can make a split-second decision in a hurry, and make something happen.

That was evident on his signature play of the night. On a fourth-and-1 from the Detroit 29, Manziel, listed at 6-0, 210, took a snap from the I-formation and rolled out to his right. Fullback Ray Agnew was open in the flat, but Manziel's vision was obstructed by onrushing linebacker Kyle Van Noy.

For a brief instant – like the same time that Agnew was open – it looked as though Manziel was about to get crushed. But Van Noy couldn't corral him. Manziel slipped and squirmed out of that mess, and after glancing Agnew's way again, decided to keep the football and dash to the sticks.

He got out of bounds with a one-yard gain that moved the chains, but probably ran 25 yards to get there. First down! Johnny Football magic! And at the end, he took a hit.

Maybe as he grows up, Manziel will learn to flip that football fast to his fullback.

Worried about too many hits?

"You always are," Shanahan, the Browns' new offensive coordinator, told USA TODAY Sports as he walked to the buses. "Especially when guys scramble around and try to make those plays. It's a fine line."

Now it's Shanahan's job to collaborate with Manziel and manage this.

Manziel had a few good throws, completing 7 of his 11 passes of the short and intermediate variety. There wasn't much to be seen of his strong arm on the deep throws.

But his footwork was surely on display. Manziel had a team-high 27 yards on six carries. You can only imagine how much he may have run if he had played a full game.

This is not the formula for long-term success as an NFL quarterback.

"Obviously, that's not the plan for me to get that many carries every week," Manziel said. "But at the same time, the more and more I get better at progressions, the more and more I get comfortable with the play-calls and the scheme and what we're trying to do…hopefully that'll weed down."

Shananhan knows what Manziel means. In his previous job as Washington's coordinator, he crafted the offense that facilitated Robert Griffin III's breakout rookie season.

Griffin was NFL Offensive Rookie of the Year, and he sparked a late-season run to the playoffs.

But Griffin's rookie year ended with a shredded knee, and he hasn't been the same since.

The Browns offense, at least when Manziel was in the game, resembled the RGIII-fueled scheme for Washington in 2012, with the pistol formation and read options. Manziel likes it, as these features constitute a takeoff from the scheme he flourished in at Texas A&M.

"I don't want to put too much pressure on him," Shanahan said. "I want to be able to do something he's comfortable with."

The read-option plays can force the defense to hesitate and adjust, but this must be weighed against the additional risk and hits on the quarterback. To win and survive in the NFL, Manziel – and Griffin, too, for that matter – must be able to slice up defenses from the pocket.

You know what they're thinking. If you can do both, even better.

They just can't ignore the risk. On Saturday night, Manziel and Shanahan were upbeat about the quarterback's ability to protect himself and limit exposure. He got out of bounds. He slid to avoid a hit. He was smart about his running, not getting too greedy.

But that was one game, against backups. Whenever Manziel wins the job – it's a matter of when, not if – the tests will come against even faster, more powerful defenders.

Strikingly, Manziel's longest run – 16 yards – came on a third-and-eight that started with him in the shotgun. After checking maybe a couple of his progression, he bolted from the pocket. And slid safe.

That's what he offers that Hoyer doesn't. He can improvise and make a play.

Yet it was also striking that Hoyer, in his first game since tearing an ACL in early October 2013, said he didn't take a single hit during his one-and-a-half quarters of duty.

On Saturday night, the Browns had distinct game-plans, depending on the quarterback.

"It's give and take," Shanahan said. "You really don't know what people can do until you put them in the game."

Browns coach Mike Pettine has indicated that he will pick his starter before the third preseason game, against the St. Louis Rams on Aug. 23. It seems logical that Manziel will start at Washington on Monday night, but that's officially still up in the air.

"We're still determining it," Shanahan said.

Yet he knows what needs to come next for Manziel.

"Either way," Shanahan said, "he will get him some time with the ones."

Johnny Manziel received his first regular-season action in Week 2, taking three snaps against the Saints. The rookie handed off twice and threw one incomplete pass in the Browns' come-from-behind win. (Photo: Andrew Weber, USA TODAY Sports)

Browns players and coaches have praised Manziel's early approach, showing appreciation for his work ethic and willingness to keep a low profile in the locker room, something rookies are generally expected to do no matter how famous. (Photo: Andrew Weber, USA TODAY Sports)

Tutoring Manziel will be Cleveland offensive coordinator Kyle Shanahan, who helped Robert Griffin III to offensive rookie of the year honors with the Redskins in 2012. (Photo: Andrew Weber, USA TODAY Sports)

Arizona Cardinals wide receiver John Brown (12) dives as he catches a pass for a touchdown in the second half against the Cincinnati Bengals at University of Phoenix Stadium. (Photo: Mark J. Rebilas, USA TODAY Sports)

Cincinnati Bengals quarterback Andy Dalton (14) throws just before being hit by Arizona Cardinals defensive end Frostee Rucker (98) during the first half at University of Phoenix Stadium. (Photo: Matt Kartozian, USA TODAY Sports)

Atlanta Falcons wide receiver Devin Hester (17) breaks a tackle by Tennessee Titans defensive back Tommie Campbell (37) on his way to a touchdown during the first quarter at the Georgia Dome. (Photo: Dale Zanine, USA TODAY Sports)

Minnesota Vikings wide receiver Cordarrelle Patterson (84) jumps into the crowd after scoring a touchdown against the Kansas City Chiefs in the first half at Arrowhead Stadium. (Photo: John Rieger, USA TODAY Sports)

Houston Texans quarterback Ryan Fitzpatrick (14) checks off at the line of scrimmage in the first quarter of a preseason game against the Denver Broncos at Sports Authority Field at Mile High. (Photo: Ron Chenoy, USA TODAY Sports)

New York Jets wide receiver Eric Decker (87) is congratulated by offensive guard Brian Winters (67) after scoring a touchdown against the New York Giants during the second half at MetLife Stadium. (Photo: Adam Hunger, USA TODAY Sports)

New York Giants fullback Henry Hynoski (45) scores a touchdown as he is tackled by New York Jets free safety Jaiquawn Jarrett (37) during the second half at MetLife Stadium. (Photo: Adam Hunger, USA TODAY Sports)

Seattle Seahawks running back Christine Michael (33) points to the sky after scoring a touchdown against the Chicago Bears off a pass thrown by Seattle Seahawks quarterback Russell Wilson (3) during the first half at CenturyLink Field. (Photo: Steven Bisig, USA TODAY Sports)

Philadelphia Eagles tight end Brent Celek (87) makes a catch and has his helmet knocked off by Pittsburgh Steelers inside linebacker Lawrence Timmons (94) during the first quarter of a game at Lincoln Financial Field. (Photo: Bill Streicher, USA TODAY Sports)

Denver Broncos wide receiver Demaryius Thomas (88) tries to break free from the hold of San Francisco 49ers defensive back Perrish Cox (20) after making a catch in the first quarter at Levi's Stadium. (Photo: Cary Edmondson, USA TODAY Sports)

Indianapolis Colts quarterback Andrew Luck (12) makes hand signals while at the line of scrimmage against the New York Giants in the first half at Lucas Oil Stadium. (Photo: Brian Spurlock, USA TODAY Sports)